Automatic block signaling system for railroads



July 26, 1938.

E. c. LARRY ET AL AUTOMATIC BLOCK SIGNALING SYSTEM FOR RAILROADS Filed May 24, 1935 2 Sheets-Sheet 1 iai gl V. U n g m IINVENTORS. ECLar'ry and MCTwiTc heH 51%?Til5 7 m BY M M THEIR ATTORNEY.

July 26, 1938; E. c. LARRY ET AL ,2

AUTOMATIC BLOCK SIGNALING SYSTEM FOR RAILROADS Filed May 24, 1935 2 Sheets-Sheet 2 .h m m 5. n R Nn T T W A n m a H Q T E w Patented July 26, 1938 AUTOMATIC BLOCK SIGNALING SYSTEM FOR RAILROADS Edwin 0. Larry, Rochester, and Morton Cr Twitchell, Spencerport, N. Y., 'assignors to General Railway Signal Company, Rochester,

Application May 24, 1935, Serial No. 23,268

19 Claims.

This invention relates to automatic block signaling systems preferably of the absolute-permissive-block type, and more particularly to a primary-secondary track relay combination coordinated with other relays and devices of such asystem.

' In accordance with the present invention it is proposed to so interconnect a primary track relay and a secondary or repeater track relay, that the secondary relay will in accordance with the position it assumes change the pick up and drop away characteristics of the primary relay, so as to result in a more sensitive and reliable track circuit current detecting combination, and to perform other functions by this primary-secondary track relay combination. As is well understood by thoseskilled in this art, the signaling apparatus of an absolute-permissive-block signaling system absolutely blocks the movement of trains in an opposite direction to that of a first train in a single track section and affords permissive follow up movement of trains in the same direction through such section, and this type of system usually employs a directional stick relay for permitting such follow-up move. More specifically it is proposed in accordance with the present invention to so coordinate the primarysecondary track relay combination with thedirectional stick relay of the absolute-permissive- 30 block system, that the primary track relay, which is the first to drop due to the presence of a train moving in a particular direction, will close a pickup circuit for such stick relay and so that the stick circuit for such stick relay is controlled at least indirectly by the secondary relay.

In accordance with one form of the invention as illustrated in Fig. 2 of the drawings it is further proposed to so interconnect the primary and secondary relay of the track relay combination in that the wayside signal must give a stop indication for each deenergization of the repeater or secondary track relay directly in advance of such signal, before reenergization of the secondary track relay can take place. This feature provides a check on the failure of a signal to assume the stop position, because failure of a signal to go to stop causes the secondary relay to remain down and this in turn causes the next signal in the rear to assume a caution or a stop position, even 50 though more favorable trafiic conditions exist in advance thereof.

Other objects, purposes and characteristic features of the present invention will in part be described hereinafter and will in part be obvious from the accompanying drawings, in which:-

Fig. 1 illustrates one embodiment of the present invention, in which embodiment the wayside signals are multiple aspect color light signals and therefore do not require checking of the movement of the signal to stop, since the signals have no moving parts; and

Fig. 2 shows a modified form of the invention applied to movable spectacle color light signals and including means for checking the movement of the signal spectacle to the stop position in response to trafiic conditions requiring such an indication.

Figure 1 Referring to Fig. 1 of the drawings, in which only a portion of a single track section of railway track has been illustrated, the track rails I have been divided by insulating joints 2 into isolated sections, of which each two adjacent sections comprise a block, and of which the block N and portions of the blocks M and 0 only have been illustrated. Each of these isolated sections is provided with a track circuit which comprises a battery B, the track rails l and a track relay T in series. This track relay T comprises part of the primary-secondary track relay combination heretofore mentioned. Since these various track circuits are the same, each of the reference characters for the track batteries and track relays have been provided with a prefix corresponding to the prefix for the signal with which the track circuit is directly associated.

. At the entrance to each block for each direction of traffic is provided a wayside signal, and for convenience the west bound signals have been designated ISG and 3SG, whereas the east-bound signals have been designated 2SG and 48G. Each of these primary track relays is interconnected with an associated secondary track relay 1?, having a prefix corresponding to the prefix of the associated primary track relay. Since like parts employed in the control of each of the signals are the same the control circuits and devices of the signal ZSG will only be described, like parts for the remaining signals being assigned like reference characters having distinctive exponents or prefixes, as the case may be.

As shown in the drawings the secondary relay, or track repeater relay ZTP, is controlled by the contact ll) of the primary track relay 2'1, and this relay 2TP when energized includes through the medium of its make-before-break contact I l agreater or less portion of the winding of the track relay 2T, depending upon whether the secondary relay is in its energized or deenergized Condition. In other words, when the repeater track relay ZTP is in its retracted condition it ill-- cludes the entire winding of the track relay 2T, whereas if the repeater track relay ZTP is in its attracted condition it includes in the track 'c'irf cuit only apo'rtion of the winding of the track relay 2T. This expedient of changing the sensitivity of the track relay is resorted to in .order to render the track relay more readily responsive to current when it is to be picked up and to render it more responsive to the shunting action of a train when it is energized and is to be deenergized by such train.

The signal ZSG is a three color aspect signal of the multiple unit color light type, which. has no moving parts, a particular color unit being illu minated under a particular condition of traflic. The three color light units G, Y and R of this signal ZSG emit color beams of green, yellow and red, respectively, signifying clear, caution and stop conditions, respectively. As is readily apparent from the circuits for these signal units, the proceed lamp G is lighted when the homedistant relay ZI-ID is energized by current of positive polarity, the caution lamp Y is energized when this'relay ZHD is energized by current of reverse polarity and the stop unit R is energized when the relay ZI-ID is deenergized.

Each signal has associated therewith the usual directional stick relay, which, for the signal ZSG comprises the. stick relay 23. This stick relay 2S isprovided'with one pick-up circuit and two stick circuits. The pick-up circuit for the relay 2S includes the front contact ll of the relay ZHD,

and the back contact I3 of the relay 2T. One

stick circuit for this relay 28 includes its own stick contact 14 and the back contact I3 of the relay 2T, and the other stick circuit includes the stick contact Hi and the back contact 24 of the relay Z-HD, e The home distant relay 2HD is a relay of the polar neutral-retained type, which includes a polar armature and a neutral armature, and of which the neutral armature will be retained during pole changing of the current for the relay; this neutral armature being provided with an auxiliary electro-magnet 5 inductively coupled to the main winding-of the relay, sothat during pole'ohanging of the current in the main wind a current is induced in the auxiliary electromagnet 5 to holdthe neutral armature up during such pole changing; operation. Fora more "detailed description'of a relay of this type atten tion is directed" to the patent to Larson No.

. 1,852,210 dated April 5, 1932. This relay ZHD is normally energized through a circuit which may be traced as follows: beginning at the terminal 3+ of a suitable source of current B located at the next signal location in advance, front contact I6 of the'relay lHD, front contact I! of the track repeater relay 3TP, front contact l8 of the repeater track relay 2TP, winding of the relay ZHD to a common return wire 0 connected tothemidpoint of the source B at the next signal in advance. Under caution trafiic conditions this relay 2HD.is energized by current of the opposite polarity through a circuit including in series the fronticontact I9 ofthe stick relay 45, the back contact TIE? of the relay 4HD, and the contacts ligand I3?.heretoforementioned.

Operation Figure 1 I In order to obtain a clear understanding or" the operation of, the system, it is believed only necessarrierensi e lla govemen or atrainfrom left t right through the blocks N and 0. Let us assume that such a train is moving in an eastwardly direction, rom left to right, in the block M. The entrance of this train into the block N will cause deenergization of the track relay 2T, which track relay 2T upon dropping will close a pick-up circuit for the relay 2S and will break the energizing circuit for the repeater track relay ZTP. This closure of the back contact l3 of the relay 2T will cause the relay 28 to be picked up. Also, dropping of the repeater track relay 2TP will cause opening of the contact I8 in the energizing circuit of the relay 2HD, thus causing deenergization of this relay 2HD. Dropping of the relay. 2HD will result in dropping of its contacts 12 and 24 thereby opening the pick-up circuit heretofore traced for the relay 2S and closing the second stick circuit for this relay 2S. Dropping of relay ZHD will also cause the signal ZSG to display'a danger indication by the lighting of the red lamp. R. It is thus seen that the pick-up circuit for the relay 2S is directly controlled by the primary track relay 2T, whereas one of the stick circuits for this relay 28 is controlled by the repeater track relay 2TP through the medium of relay ZED, and that a certain amount of time must elapse following the dropping ofthe track relay 2T, before the contact I2 of the relay 2HD may assume its. retracted position to break the pick-up circuit, and that this time delay is in part provided by the intervening secondary relay 2TP. In other words, the pick-up circuit for the relay 28 is controlled by the primary portion of; the primary-secondary track relay combination; whereasthe stick circuit is controlled by thesecondary portion of this combination. Also, this primary-secondary track relay combination ZT-Z'IP in itself constitutes a rather sensitive train detecting mechanism, in that the track relay 2T is so controlled by its repeater track relay 2 TP that it is sensitive to train shunting when in its attracted condition and is sensitive to train unshunting when it is in its retracted condition.

As the train in question now. proceeds in an eastward direction through the block N, it will uponleaving the first track circuit of block N 2 T- 2TP to assume the attracted position. This willnot, however, cause deenergization, of the stick relay 28, for although one stick circuit has been broken at back contact I?! of the relay 2T, the other stick circuit including back contact 24 of relay ZHD is still closed.

Let us now assume that the train in question enters the block 0. When this occurs the stick relay 4S willbe picked up and stuck up in the same manner as already explained in connection with relay 28. As the rear end of the train now leaves theblock N the relays 3T3TP pickup and with the stick relay 48 now energized current of negative polarity is applied to the relay 2HD. This will cause the yellow lamp Y of the signal ZSG to be lighted. 7

As the train under consideration now entirely passes out of the block 0, the relay 4HD is reenergized. This causesthe relay 2HD to again be energized by current of normal polarity as a result of which the signal lamp. G of thesignal ZSG is again lighted. As this train continues its eastward. journey the signal 4SG will be returned to its normal clear condition, all in a manner as already explained in connection with signal 28G.

the present invention, also shown applied to a single track portion including the block N and portions of the blocks M and O. In this form of the invention like parts have been designated by like reference characters as corresponding parts of Fig. 1. Also, like parts for each signal location have been designated by like reference characters with exponents or prefixes corresponding to that of the signal location at which it is located. It will be noted that the track relays, repeater track relays, and directional stick relays have been identified by the same reference characters as those shown in Fig. 1.

Attention is particularly directed to the fact that movable spectacle light signals S S S and S have been shown instead of fixed aspect light signals ISG, 28G, 38G and 48G as shown in Fig. 1, and that the light signals of Fig. 2 are directly controlled by a line circuit extending through the block to the next signal in advance as a result of which the home-distant relays HD are omitted from Fig, 2 of the drawings. An additional and slow acting relay GY, is also shown for each signal location in Fig. 2, this relay GY being energized when the signal mechanism assumes either the proceed (G) or the caution (Y) position, and providing that the associated repeater track relay is in its energized position.

Referring to the signal S for instance, this signal includes only a single signal lamp L which in the particular form of the invention illustrated is energized only When the opposing track repeater relay ITP is deenergized, as illustrated by the circuit through the back contact 20 of the track relay ITP, thus aifording the usual approach lighting feature.

The structure of the signal S is such that if its winding 2| is energized by current of normal polarity the spectacle 22 is moved to its extreme right-hand position in which the green filter G intercepts the light emittedby the lamp L so as to leave only green light in the emitted beam, suitable lens structure of course being used to produce a concentrated beam of light. Under this condition the contact g assumes a right-hand position and results in energizing the clear-caution relay ZGY through a circuit including the front contact 23 of the relay 2TP. Also, if the winding 2| 2 of the signal S is energized by current of reverse polarity, the spectacle 22 is moved to its extreme left-hand position, in which the yellow filter Y intercepts the light from the lamp L thus emitting a yellow beam of light. Under this condition, the contact 9 of this signal mechanism assumes a pendent position and the contact y assumes its left-hand position, thus causing the energization 'of the clear-caution relay 2GY.

Under normal conditions the winding 2 l of the signal S is energized through the following circuit:beginning at the terminal. of a suitable source of current at the next signal in advance, front contact 21 of the relay lGY, back contact 28 of the relay 3S, front contact 29 of the relay STP, front contact 30 of the relay 2T'P, winding M and front contact 3| of the relay 4 GY to the other terminal of said source. If now the winding 2| 2 of the signal S? is deenergized, as it would be byatrain entering the block N, the signal spectacle 22 willbe turned to its middle biased position, under which C0117;- dition the two contacts g and y will assume their pendent position, in which position of the mech, anism the pick-up circuit for the relay 2TP, traced hereinafter, may be closed. Also, with the mechanism of the signal S in its middle biased position the red color filter R intercepts the light beam and causes a red signal indication to be given thus manifesting danger ahead. For a more detailed illustration and description of this movable spectacle signal attention is directed to the prior application of Field Scr. No. 561,802 filed September 8, 1931. Under normal clear trafiic conditions the repeater track relay ZTP is energized through a stick circuit including the front contact 34 of the track relay 2T and its own stick contact 35 Operation Figure 2 Let us assume that there is a train moving from left to right in the block M under clear conditions of traffic in advance. The presence of the train in the block M will result in deenergization of the repeater track relay ITP, resulting in closure of the back contact 20 and resulting in illumination of the lamp L thus manifesting to the engineer that traffic conditions in advance are clear. As this train passes the signal S its treading upon the track circuit including the track relay 2T will cause deenergization of this primary track relay 2T and opening of the front contact 34 as a result of which the stick circuit for the secondary track relay TP is broken, thus causing the repeater track relay ZTP to also assume the retracted position. Deenergization of the repeater track relay 2TP will of course change the sensitivity of the track relay 2T by movement of the make-before-break contact II to its lower position. Also dropping of the track relay 2T will cause closure of back contact 34 of this relay, thereby closing a pick-up circuit for the relay 28, which includes the back contact 34 of relay 2T and the front contact 36 of the relay ZGY. Also, dropping of the repeater track relay ZTP will by dropping of its contact 30 result in deenergization of the winding M of the signal S and will further result in opening of the contact 23 included in the energizing circuit for the relay ZGY. Dropping of relay 2GY will by closing its back contact 31 close a stick circuit for the relay 28, which stick circuit includes the stick contact 38 of the relay 23. The stick relay 2S was, however, already stuck up through a stick circuit including the back contact 34 of the primary track relay 2T. It is thus seen that the directional stick relay 25 is picked up by dropping of the track relay ET and is stuck up by dropping of the relay 2GY con trolled by the track repeater relay 2TP. It should be noted that the directional stick relays of Fig. 2 are the same as those in Fig. 1 except that contacts of the clear-caution relay are used instead of contacts of the home-distant relay.

With the directional stick relay 28 now energized, and with the relay ZGY deenergized, current of negative or caution potential is applied to the signal mechanism of the next signal in the rear through a circuit starting at the terminal associated with the contact g, the contact 9 assuming its left-hand pendent position, the contact 1 assuming its right-hand pendent position, the front contact 40 of the directional stick re-- lay 23, the back contact 3l of the relay ZGY, to the next signal in the rear, and then back through front contact 29 of relay ITP, back contact 28" of relay IS and back contact 2-1 of relay ZGY to the terminal It will be noted that the line circuit extending from a particular signal the pick-up and stick circuits for I I to the next signal in advance includes front con- 7 tacts of the two track repeater rela 's of the block along which this line circuit extends, and that deenergization of these track repeater relays will result in opening the line circuit and in shorting it insofar as the portion of the circuit toward the signal control windingll is concerned. This is done in order to afford additional protection, so that the signal is not apt to be operated by foreign current accidentally applied to the line wire, as sometimes occurs by accidental crossing of line wires.

As the train in question moves from left to right through the block N the signal mechanism for the signal S will of course remain in its middle stop position, and the lamp L of this signal will be extinguished as soon as the rear end of the train has left the block M. Let us now assume that the train in question enters the block In so doing the stick relay 4S will be picked up in a manner as already explained in connection with the stici; relay is.- As the rear end of the train leaves the track circuit including the track relay 2T, this primary track relay 2T will pick up, and the picking up of this primary relay 2T will result in picking up of the repeater track relay 2'IP' through the following pick-up circuit-beginning at the terminal (-1-) of a local source of current, contact 9 of the signal S assuming its pendent position, contact 3 of this same signal assuming its pendent position, front contact 42 of the track relay 2T, through the winding of the secondary track relay ZIP to the other terminal of said source. It should, however, noted that this secondary track relay ZTP would not have been picked up had the signal S2, for some reason or another, stuck clear and not have assumed the stop position. e e

It is thus seen that if a signal, such asthe signal S for instance, should be stuck in its clear or caution position even though a passing train has deenergized the repeater track relay ZTP the next signal in the rear could not receive caution energy because the circuit to such signal in the rear would be open at the contact g or y, as the case may be. Also, since the secondary track relay 21? cannot be picked up under this conditionthe relay 2GY would remain deenergized and the clear circuit to the next signal in the rear cannot be closed at front contacts 21 and 3 I In other words, the signal must follow each deenergization of its relay TPcr the next signal in the rear will remain thereafter at stop. As the rear end of the train in question now passes entirely out of the block N resulting in reenergization of the repeater track relay3'IP, the signal mechanism for the signal S will be energized by current of negative polarity through a circuit such as heretofore traced and including back contacts 27 and 3! of the clear-caution relay 4GY, the front contact 661 of the stick relay 4S and the contacts '9 and y of the signal S". The application of this current of negative polarity to the winding M of the signal S will result operation of the signal mechanism to the caution position, Where the light beam is intercepted by the yellow color filter Y, and in the event of a train moving from left to right in the block M the lamp L of the signal S would be lighted to produce such yellow color beam. This application of current of reverse polarity to the winding of the signal S and with'the repeater track relay 2TP already energized, as heretofore assumed, the relay ZGY is again energized, as a result of which current of positive polarity is applied tethenext signaiimtne rear of'sig'nal s through the mediumof fr r contacts 21 and 3l of this-relay rGY, Also, deenergization of the stick're'ley is-results, this by reason of opening of theback contact 31 of relay ZGY, the back contact 3 l -a1rea'dy having been opened when the rear'end of the train left the track circuit includingthe primary' track circuit ZT. As the train iiuestion now continues its movement from lento right through the block 0, the sigrial S and all of the-relays associated therewith will be "returned to their normal position as already explained in connection with the signal 5 The system shown in Fig. 2 of applicants disclosure therefore not only discloses a system of absolute-permisSive-blOck signaling in which a directional stick relay is picked up through a back contact of a primary relay and is stuck up through a front contact controlled by a secondary relay of a primary-secondary track relay combination in which the secondary relay changes the sensitivity of the primary relay, but further pro- I vides means whereby the secondary relay 'of such trackrelay combination constitutes a stick-relay which can only be picked up if the signal directly'ass'ociated therewith has moved'to the stop position in response to deene'rgization of such secondary relay. This stick feature of'the secondary relay of the track relay combination causes the next signal in the rear to remain at stop in the event the associated signal sticks in a proceed position, thereby advising the engineer and'the signal maintainer that a signal has accidentaliy stuck at clear or caution, so that the trouble may be corrected. In both forms of the invention illustrated the primary-secondary track relay combination performs the double function of constituting a sensitive current detecting means for manifesting the presence or absence of a train on the track circuit and comprises a quick dropping primary track relay which may serve to close a pick-up circuit for a directional stick relay together with a secondary track relay whichmay close a stick circuit for this directional stick relay which will hold such directional stick relay energized until the entire block in advance of such stick relay becomes unoccupied.

Having thus shown and described several embodiments of the present invention to show how the invention may be applied to different kinds of wayside signals it should be understood that the particular embodiments selected'havenot been selected to show the scope of the invention but have been selected to illustrate the nature of the invention and how it may be applied to several well known forms of signaling systems, and it should further be understood that various changes and'modifications may be made to adapt the invention to other signaling systems, all without departing from the spirit or scope of the present invention except as demanded by the scope of the following claims. I

What we claim as new is:--

1. In a railway signal system of the absoluteprmissive-block type, the combination with a single track section of railway track, signals capable of indicating clear, caution and stop for governing traffic in one direction through said section, signals also capable of indicating clear, caution and stop for governing traffic in the opposite direction-through said section, circuits for governing said signals so organized that the passage of a train through said section will cause all opposing signals to assume the stop condition and to cause the signals governing traffic in the same direction to assume a stop condition as the train passes the same, a stick relay associated with each signal for when energized tending to cause the next signal in the rear to assume a caution condition, a track relay associated with each signal, a repeater track relay for each track relay energized when such track relay is in its attracted condition, means for changing the effectiveness of the Winding of each track relay for each unit of current flow in accordance with whether said repeater relay is in its attracted or retracted condition, a pick-up circuit for each stick relay including a back contact of its associated track relay, and a stick circuit for each stick relay including a contact controlled by its associated repeater track relay and closed when such repeater track relay is deenergized.

'2. In a railway signal system of the absolutepermissive-block type, the combination with a single track section of railway track, signals capable of indicating clear, caution and stop for governing traffic in one direction through said section, signals also capable of indicating clear, caution and stop for governing traific in the opposite direction through said section, a polar relay for each signal, a stick relay for each signal, a circuit for each polar relay extending to the next signal in advance and connected to a source of one polarity when the polar relay associated with said next signal is energized and connected to a source of the reverse polarity when the polar relay associated with said next signal is deenergized and its associated stick relay is energized, a track relay associated with each signal, a repeater track relay for each track relay picked up through a front contact of said track relay, means for changing the efiectiveness of the winding of each track relay for each unit of current flow in accordance with whether said repeater relay is in its attracted or retracted condition, a pick-up circuit for each stick relay including a back contact of its associated track relay, and a stick circuit for each stick relay including a contact controlled by the associated repeater track relay and closed when such repeater track relay is in its retracted condition. y

3. In an automatic block signaling system of the absolute-permissive-block type, the combination with a section of single track, of a polar electro-responsive signaling device at the entrance, to each block of said section for each direction of travel through said section, a directional stick relay for each signaling device, a circuit for each signaling device extending to the next signaling device in advance and connected to a source of current of one polarity when such signaling device in advance is energized and connected to a source of current of the opposite polarity when such signaling device in advance is deenergized and its associated stick relay is energized, a track relay for each end of each block one such track relay for each signaling device, a repeater track relay for each track relay having included in its energizing circuit a front contact of said track relay, contacts on said repeater track relay for rendering said track relay more responsive to each unit of current whensaid repeater track relay is in its retracted condition than when in its attracted condition, a pick-up circuit for each directional stick relay including a back contact of the associated track relay, and a stick circuit for each directional stick relay including a contact closed in response to the deenergization of its associated repeater track relay.

4. In an automatic block signaling system of the absolute-pernflssive-block type, the combination with a section of single track, of a polar electro-responsive signaling device at the entrance to each block of said section for each direction of travel through said section, a directional stick relay for each signaling device, a circuit for each signaling device extending to the next signaling device in advance and connected to a source of current of one polarity when such signaling device in advance is energized and connected to a source of current of the opposite polarity when such signaling device in advance is deenergized and its associated stick relay is energized, a track relay for each end of each block one associated with each signaling device, a second stick relay, a pick-up circuit for said second stick relay including a front contact of its associated track relay and a contact closed only if the associated signaling device is in its stop condition, a stick circuit for said second stick relay including a front contact of the associated track relay, contacts on said second stick track relay for rendering said track relay more responsive to the flow of current when said second stick relay is in its retracted condition than when in its attracted condition, a pick-up circuit for each directional stick relay including a back contact of the associated track relay, and a stick circuit for each directional stick relay including a contact closed in response to deenergization of the associated second stick relay.

5. In a railway signal system, the combination with a railway track divided into sections by insulating joints, a track circuit for one of said sections and including a track relay at one end and a track source of current at the other end, a movable spectacle signal adjacent said track relay capable of indicating clear and stop, a secondary track stick relay, means controlled by said secondary track stick relay for changing the responsiveness of said track relay to current in accordance with whether said secondary track stick relay is in its attracted or retracted condition, a control circuit for said signal controlled by a front contact of said secondary track stick relay, a pick-up circuit for said secondary track stick relay including a front contact of said track relay and a circuit portion closed only when said spectacle assumes the stop position, and a stick circuit for said secondary track stick relay including only its stick contact and a front contact of said track relay, whereby said secondary track stick relay cannot be reenergized if said signal did not assume the stop position in response to deenergization of said stick relay.

6. In a railway signal system, the combination with a railway track divided into sections by insulating joints, a track circuit for one of said sections and including a track relay at one end and a track source of current at the other end, a movable spectacle signal adjacent said track relay capable of indicating clear and stop, a secondary track stick relay, contacts on said secondary track stick relay which when in their attracted position include less turns of the winding of said track relay in said track circuit than when in their retracted position, a control circuit for said signal controlled by a front contact of said secondary track stick relay, a pick-up circuit for said secondary track stick relay including a front contact of said track relay and a circuit portion closed only when said spectacle assumes the stop position, and a stick circuit for said secondary track stick relay including only its stick contact and a front contact of said track relay, whereby said secondary track stick relay cannot bereenergized if said signal did not assume the stop position in response to deenergization of said stick relay.

"I; In a railwaysignal system, the combination with'a railway track divided into sections by insulating joints, a'track circuit for onecf said sections and including a track relay at one end and a track source of current at the other end, amo-vable spectacle signal adjacent said track capable of indicating clear and stop, a secondary track stick relay,'make-before-break contacts on said secondary track stick relay which when in their attracted position include less turns of the winding of said track relay in said track circuit than'whenin theirretractedposition, a control circuit for said signal controlled by a, front contactof said secondary track stick relay, a pickup circuit for said secondary track stick relay including a front'contact of said track relay and a circuit portion closed only when said spectacle assumes the stop position, and a stick circuit for said secondary track stick relay including only itsstickcontact and "a front contactof said track relay, whereby said secondary track stick relay cannot be ,reen'ergized if said signal did not assume the stop position in response to deenergization'of said stick-relay; a

8. In a railwaysignal system; the combination With'a wayside signal of the movable color aspect type capable of indicating proceed and stop, of a track circuit directly ahead of said signal including the usual track source of current and a primary track relay of a primary-secondary track relay combination, said primary-secondary track relay combination including a secondary relay for changing the pick-up sensitivity of said primary relay to current flow in accordance with whether said secondary relay assumes its attracted or its retracted condition, a circuit for operating said signal to the clear position including a front contact of said secondary relay, a pick-up circuit for said secondary relay including a front contact of said primary relay and contacts of said signal closed only if said signal assumes a stop position, and a stick circuit for said secondary relayincluding its own front contact and a front contact of said primary relay. V n

9. In a railway signal system, the combination with a wayside signal of the movable color aspect type capable of indicating proceed and stop, of a track circuit directly ahead of said signal including the usual track source of current and a primary track relay of a primarysecondary track relay combinatiomsaid primarysecondary track relay combination including a secondary relay for changing the sensitivity of the Winding of said primary relay to the flow of current in accordance with whether said secondary relay assumes its attracted or its retracted condition, a circuit for operating said signal to the clear position including a front contact ofsaid secondary relay, a pick-up circuit for said secondary relay including a front contact of said primary relay and contacts of said signal closed if said signal assumes a stop position, and a stick circuit for said secondary relay including its own front contact and a front contact of said primary relay, a directional stick relay for indicating the direction of movement of a train by said signal, a proceed relay, an energi'zingcircuit for said proceed relay closed only :when said signal is ina proceed condition, a pickupcircuit'for'said directional'stick relay including' a'front contact of said proceed relay and a back contact of said track relay, and a stick circuit for said directional stick rela'y including its own front contactand a back contact of said proceed relay;

10. In combinatiom'a railway track having two adjacenttrack sections, a track circuit foreach track section. including'in series therein'a'primary track relay, a secondary track relay for each primary relay for changing the responsiveness of said primary relay'to current'flowin' accordance with whether said secondary relay a'ssumes its attracted or retracted'position and-com trolled to repeat the position of said primary relay, a directional stick relay',ia'pick-up circuit for said directional stick'relayincluding aback contact of a. primary relay 'ofrone track section anda front'contact controlled by the secondary relay of the next track section'in' advance, and a stick circuit for said stickrelay controlled by said secondary relay-0f the next track section in advance.

11. In combination-,a railway track having two 7 adjacent track sections, a track circuit for each track section including in series therein a primary track relay, a secondary track relay for each primary relay for changing the responsiveness of said primary-relay to'current flow in accordance with'whether said secondary relay as sumes its attracted or-retracted position and controlled.- torepeat-the position of said primary relay, a directional stick relay, 1 a pick-up circuit for said directional stick relay including a back contact of a'primary relay of one track section and'a contact closed only if the associatedsecondary relay and the secondary relay ofthe next track section in=advance--areenergized, and a stick circuit closed at least as long as one of said secondary relays is deenergized. a

- l2-.- Ira-combination, a primary track-relay included in'a normally closedtrackcir'cuit for a railway track section, a a secondary track a relay associated with said primary relaycontrolled to repeat the condition of such'primar-y relay-and in turn change the responsiveness of such primary relay to the flow-of current in accordance with whether said secondary 'relayassumes its Vattracted orzretracted position,- a pick-up circuit for said-secondaryrelayinc1uding a front contact of its associated primary'relay and a back contact of an electro-respons'ive means which electroresponsive means is controlled by said secondary relay and a stick circuit for said'secondary relay including a-{ront contact of said primary relay, whereby said secondaryrelay cannot" be picked up until said electro-responsive means has followed the previous deenergization of said secondary relay.- r r .7 13. In a railway signal system, the combination with a railway track divided into sections by insulating joints, a track circuit'for one of said sections and including a track relay at one end and a track source of current at the other end, a railway signal adjacent said track relay capable of indicatingclear and stop, a secondary track stick relay, ri-ieans controlled by'said secondary track stickrelay for changing the responsiveness of said track'relay to current flow in accordance with whether said second'arytrackstick relay is'in its attracted or retracted condition, a control circuit for said, signal controlled by a from contact of said secondary Itrack stick .relay', a

pick-up circuit for said secondary track stick relay including a front contact of said track relay and a contact closed in response to opening of said control circuit, and a stick circuit for said secondary track stick relay including only its stick contact and a front contact of said track relay, whereby said secondary track stick relay cannot be reenergized if said control circuit was not opened in response to deenergization of said stick relay.

14. In combination, a track circuit, a primary track relay included in said track circuit, a secondary track relay of the stick type, a pick-up circuit for said secondary relay including a front contact of said primary relay and a contact of an :electro-responsive device closed only when said electro-responsive device is deenergized, a stick circuit for said secondary relay including its own stick contact and a front contact of said primary relay, means controlled by said secondary relay to cause said primary relay to be more responsive to the flow of current when said secondary relay is deenergized than when energized, and a. circuit for said electro-responsive device controlled said secondary relay.

15. In combination, a primary track relay included in a normally closed track circuit for a railway track section, a secondary track relay associated with said primary relay controlled to repeat the condition of such primary relay and in turn change the responsiveness of such primary relay to the flow of current in accordance with whether said secondary relay assumes its attracted or retracted position, a pick-up circuit for said secondary relay including a front contact of its associated primary relay and a contact of an electro-responsive means controlled by said secondary relay which responsive means is energized in response to energization of said secondary relay and which contact is closed when said electro-responsive means is deenergized, a stick circuit for said secondary relay including a front contact of said primary relay, and a railway signal controlled by said electro-responsive means, whereby said secondary relay cannot be picked up until said electro-responsive means has followed previous deenergization of said secondary relay.

16. In combination, a primary track relay included in a normally closed track circuit of a railway track section, a secondary stick relay, an electro-responsive device controlled by said secondary stick relay, a pick-up circuit for said secondary stick relay including a front contact of said primary track relay and a contact of said electro-responsivedevice, a stick circuit for said secondary stick relay including a front contact of said primary track relay, and means for changing the responsiveness of said primary track relay to flow of current in said track circuit in accordance with whether said secondary stick relay is in an energized or deenergized condition.

1'7. In a railway signal system of the absolutepermissive-block type, the combination with a single track section of railway track, signals capable of indicating clear, caution and stop for governing trafiic in one direction through said section, signals also capable of indicating clear, caution and stop for governing traffic in the opposite direction through said section, circuits for governing said signals so organized that the passage of a train through said section will cause all opposing signals to assume the stop condition and to cause the signals governing traflic in the same direction to assume a stop condition as the relay less responsive to current flowing in said track circuit, a pick up circuit for said directional stick relay jointly controlled by said primary and secondary track relays, and a stick circuit for said directional stick relay controlled by said primary track relay independent of said secondary track relay.

18. In a railway signal system, the combination with a wayside signal of the movable color aspect type capable of indicating proceed and stop, of a track circuit directly ahead of said signal including the usual track source of current and a primary track relay of a primary-secondary track relay combination, said primary-secondary track relay combination including a secondary relay for changing the current value at which said primary relay will pick up in accordance with whether said secondary relay assumes its attracted or its retracted condition, a circuit for operating said signal to the clear position including a front contact of said secondary relay, a pick-up circuit for said secondary relay including a front contact of said primary relay and a circuit portion including contacts of said signal, said circuit portion being closed only if said signal assumes a stop position, and a stick circuit for said secondary relay including its own front contact and a front contact of said primary relay, a directional stick relay for indicating the direction of movement of a train by said signal, a proceed relay, an energizing circuit for said proceed relay closed only when said signal indicates caution or proceed, a pick-up circuit for said directional stick relay including a front contact of said proceed relay and a back contact of said track relay, a stick circuit for said directional stick relay including its own front contact and a back contact of said proceed relay, and means for controlling the next signal in the rear controlled by said directional stick relay.

19. In a railway signal system, the combination with a wayside signal mechanism of the movable color aspect type capable of indicating proceed and stop, of a track circuit directly ahead of said signal mechanism including the usual track source and a primary track relay of a primarysecondary track relay combination, said primarysecondary track relay combination including a secondary relay for changing the picking up sensitivity of said primary relay to current flow in accordance with whether said secondary relay assumes its attracted or its retracted condition, a circuit for operating said signal mechanism to the clear position including a front contact of said secondary relay, a pick up circuit for said secondary relay including a front contact of said primary relay and contacts of said signal mechanism closed if said signal mechanism assumes a stop position, a stick circuit for said secondary relay including its own front contact and a front contact of said primary relay, and a signal lamp for said signal mechanism controlled by the approach of a train.

EDWIN C. LARRY. MORTON C. TWITCHELL. 

